The 2018 midterm elections will be critical for determining the party in power through the next several election cycles. Will Republicans maintain power or is the political pendulum swinging in Democrats’ favor?

Tight polling in many states means that question won’t be settled until Election Day in November. But one thing is for certain: Democrats will be on the defense because, of the 33 Senate seats up for grabs, Democrats hold 22 of them, while Republicans hold just eight....